St. Leo on the Eucharist

In what density of ignorance, in what utter sloth must they hitherto have lain, not to have learned from hearing, nor understood from reading, that which in God’s Church is so constantly in men’s mouths, that even the tongues of infants do not keep silence upon the truth of Christ’s Body and Blood at the rite of Holy Communion ? For in that mystic distribution of spiritual nourishment, that which is given and taken is of such a kind that receiving the virtue of the celestial food we pass into the flesh of Him, Who became our flesh. (Letter 59)